Career planning or getting out of a rut

1. Did a bachelor in Mechanical Engineering specialized Mechatronics (Controls + Electrical + Computer courses).
2. Took business courses (for general knowledge I guess)
3. Started a graduate degree in business part time
4. Managing Electrical projects (basically technical sales) (mostly business, minor use of any engineering)
5. Missed out too much in applied science and dropped out of graduate business degree

6. Now what?

To make a long story as short as possible. I always had an interest in Medical sciences and initially planned to follow a Master in Biomedical Eng. Also had in small interest in Project Management ( I think that learning how to get other to make it happen is a natural combination to being able to design anything).

My problem is, that with all this business communication and management I really feel I'm not learning as much anymore, not exploiting my curiosity, and moved to a routine of some type. I miss doing calculations, designing and coming up ways around problems.
Others do that.

Oh and I want to travel.

I do enjoy my job quite a bit, I just wouldn't mind doing some of the thinking myself.

So here are the options the way I see it now...
1 Go on this path and.... ??
2 Go do a masters in Engineering part time
3. Quit and go to a masters in Engineering full time
4. Go finish my business degree and then do this for some more years
5. Go find another job with other technical challenges ---> If i do find one, and hmm..

6. Somehow convince my boss to place me in a more technical position (which would be really hard since we are international, and I work at sales offices which would include moving and stuff ( i don't mind) but my current position being quite important I don't foresee the move for at least another full year.